#include <stddef.h>

void *memcpy(void *dst0, const void *src0, size_t len0)
{
  char *dst = (char *) dst0;
  char *src = (char *) src0;

  void *save = dst0;

  while (len0--)
    {
      *dst++ = *src++;
    }

  return save;
}